Biological particle analyzer and method of analyzing biological particles

ABSTRACT

A biological particle analyzer is disclosed and includes a microchannel including an end coupled to a first drive electrode, another end coupled to a second drive electrode, a first detection area at an upstream location and an excitation area at a downstream location for containing particles flowing from the upstream location to the downstream location inside the microchannel, a first detection circuit coupled to the first detection area for outputting a first detection result when at least one particle has arrived at the first detection area, a light emission source, and a control module coupled to the first detection circuit and the light emission source for determining when to turn on or off the light emission source according to the first detection result.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a biological particle analyzer and method of analyzing biological particles, and more particularly, to a biological particle analyzer and method of analyzing biological particles having a function of smart power savings.

2. Description of the Prior Art

A biological particle analyzer is widely used in basic research and clinical practice for Biology related fields including Cell biology, Oncology, Hematology, Immunology, Parmacology, Genetics and Diagnostics of Clinic Analysis. A Flow Cytometer is biophysical technology employed to perform simultaneously multiparametric analysis according to cell properties such as surface receptors and DNA by detecting scattered light from tested cells.

The Flow Cytometry utilizes a beam of laser light generated by a light emission source to directly light up the test cells, e.g. microparticles having a diameter 0.5˜50 micrometers. Those cells attached to fluorescent chemicals are excited by the laser light to emit scatter lights, and the scatter lights are picked up by the electronic apparatus for quality and quantity analysis of the cells. Moreover, an advanced Flow Cytometer may perform sorting and selection to purify populations of interest cells to be reused for further application. Thus, the Flow Cytometer is widely used in experiments of Immunology, Microbiology and Cell biology.

In-Home Care or Telemedicine is becoming more and more popular nowadays as it helps people make simple health examinations, e.g. blood glucose measurements, in home or in distant rural communities. Thus, there is a need to design a portable Flow Cytometer.

However, when the traditional biological particle analyzer is operating, the light emission source of the biological particle analyzer or the Flow Cytometer consumes most of the power, and the light emission source is often turned on no matter whether a test procedure is being performed, which not only wastes power but also produces a significant amount of heat. For a portable Flow Cytometer, a battery having a high capacity is required, which increases a size/volume or production cost of the portable Flow Cytometer. Worse yet, the amount of heat may shorten battery life and influence usage convenience/reliability of the portable Flow Cytometer. Therefore, how to effectively reduce the power consumption of the light emission source and keep good performance of the portable Flow Cytometer has become a goal in the field.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a biological particle analyzer and method of analyzing biological particles having a function of smart power savings.

The present invention discloses a biological particle analyzer comprising a microchannel including an end coupled to a first drive electrode, another end coupled to a second drive electrode, a first detection area at an upstream location and an excitation area at a downstream location for containing particles to flow from the upstream location to the downstream location inside the microchannel, a first detection circuit coupled to the first detection area for outputting a first detection result when at least on particle has arrived at the first detection area, a light emission source for emitting a light to the excitation area, and a control module coupled to the first detection circuit and the light emission source for determining when to turn on or off the light emission source according to the first detection result.

The present invention further discloses a method of analyzing biological particles for a biological particle analyzer comprising a light emission source and a microchannel for containing a particle flowing inside the microchannel, the microchannel comprising a first detection area at an upstream location and an excitation area at a downstream location lighted by the light emission source, the method comprising outputting a first detection result when at least one particle has arrived at the first detection area, and a control module outputting a control signal to turn on or off the light emission source according to the first detection result.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a biological particle analyzer according to a first embodiment of the present invention.

FIG. 1B is a schematic diagram illustrating an operational principle of the first detection circuit shown in FIG. 1A.

FIG. 1C is a schematic diagram of the biological particle analyzer shown in FIG. 1A according to a second embodiment of the present invention.

FIG. 1D is a schematic diagram of a biological particle analysis process according to the first and second embodiments of the present invention.

FIG. 2A is a schematic diagram of a biological particle analyzer according to a third embodiment of the present invention.

FIG. 2B is a schematic diagram of a biological particle analysis process according to the third embodiment of the present invention.

FIG. 3A is a schematic diagram of a biological particle analyzer according to a fourth embodiment of the present invention.

FIG. 3B is a schematic diagram of a biological particle analysis process according to the fourth embodiment of the present invention.

DETAILED DESCRIPTION

Please refer to FIG. 1A, which is a schematic diagram of a biological particle analyzer 10 according to a first embodiment of the present invention. The following description takes but not limited to a Flow Cytometer as an example of the biological particle analyzer 10. The biological particle analyzer 10 comprises a microchannel 100, a first detection circuit 11, a light emission source 102 and a control module 103. Two ends of the microchannel 100 are respectively coupled to drive electrodes V_(CC) and V_(SS), the microchannel 100 is used for containing a plurality of particles P₁ to flow from an upstream location to a downstream location inside the microchannel 100. The microchannel 100 comprises a first detection area A_(DET) and an excitation area A_(EXT). The first detection circuit 11 is coupled to the first detection area A_(DET) for outputting a first detection result R_(DET) to the control module 103 when at least one particle P₁ has arrive at the first detection area A_(DET). The control module 103 is coupled to the first detection circuit 11 and the light emission source 102 for outputting a control signal CTRL to the light emission source 102 according to the first detection result R_(DET), so as to control turning on or off the light emission source 102. The light emission source 102 is coupled to the control module 103 for being turned on according to the control signal CTRL to emit a light to the excitation area A_(EXT) and the particle P₁ that has entered the excitation area A_(EXT). The particle P₁ is attached to fluorescent chemicals and is excited by the light emission source 102 to emit scatter lights, such that the biological particle analyzer 10 may perform quality and quantity statistical analysis to the particle P₁ according to measurement results of the scatter lights attached by fluorescent chemicals.

Specifically, as soon as the first detection result R_(DET) indicates to the control module 103 that the particle P₁ has arrived at the first detection area A_(DET), the control module 103 outputs the control signal CTRL to the light emission source 102 to turn on the light emission source 102. The control module 103 performs timing by a built-in timer 104 to calculate a turn-on time T_(ON) of the light emission source 102, to ensure the light emission source 102 is kept turned on during the predetermined turn-on time T_(ON). When the turn-on time T_(ON) has elapsed, the control module 103 turns off the light emission source 102. The turn-on time T_(ON) may be adjusted according to different characteristics of the particle P₁, such as volume, electrical charges. As a result, the light emission source 102 is turned on only when the particle P₁ is being tested, i.e. turn-on time T_(ON), which saves unnecessary power consumption.

In short, the biological particle analyzer 10 may be notified that the particle P₁ is about to pass the excitation area A_(EXT) by the first detection circuit 11 detecting the arrival of the detection area A_(DET), such that the control module 103 turns on the light emission source 102 accordingly. When the turn-on time T_(ON) has elapsed, the control module 103 turns off the light emission source 102. Therefore, the light emission source 102 is turned on only when the particle P₁ is being tested, such that the biological particle analyzer 10 may automatically control the turn-on time T_(ON) of the light emission source 102 to achieve smart power savings.

Besides, if the first detection circuit 11 detects another particle P₂ has arrived at the detection area A_(DET) during the turn-on time T_(ON) of the light emission source 102, the control module 103 may reset the timer 104 and generate a new turn-on time T_(ON) according to the newly received first detection result R_(DET), such that the light emission source 102 is kept turned on during the new turn-on time T_(ON) to light up the excitation area A_(EXT). As a result, the biological particle analyzer 10 may automatically adjust the turn-on time T_(ON) of the light emission source 102 during the test procedure of the particles, which save unnecessary power consumption.

Noticeably, FIG. 1A illustrates one of the embodiments of the present invention, those skilled in the art may make proper modifications and not limited to this embodiment. For example, as well known in the art, the biological particle analyzer 10 works based on Electrokinetics, two ends of the microchannel 100 may be applied drive voltages having opposite polarities according to a electrically charged polarity of the particle P₁, a uniform directed electric field may be formed inside the microchannel 100, and the electrically charged particle P₁ may be attracted by the electric field to flow inside the microchannel 100, which is called Electrophoresis of an electrically charged particle. If the particle P₁ is positive electrically charged, the drive electrode V_(CC) is applied to a positive drive voltage, and the drive electrode V_(SS) is applied to a negative drive voltage. On the contrary, if the particle P₁ is negative electrically charged, the drive electrode V_(CC) is applied to a negative drive voltage, and drive electrode V_(SS) is applied to a positive drive voltage. The first detection circuit 11 is preferably a Resistive Pulse Sensor.

Please refer to FIG. 1B, which illustrates an operational principle of the first detection circuit 11. As shown in FIG. 1B, the first detection circuit 11 may be a differential amplifier 1011 including a positive input terminal V+ and a negative input terminal V− coupled to the first detection area A_(DET), and an output terminal for outputting the first detection result R_(DET). A diameter of the microchannel 100 is narrower as the particle P₁ flows closer to the first detection area A_(DET), which may align the particles flowing through the microchannel 100 into a serial stream. That is, the first detection area A_(DET) may be passed by the sole single particle P₁. Before the particle P₁ arrives at the first detection area A_(DET), a voltage difference between the positive input terminal V+ and the negative input terminal V− is a constant. When the particle P₁ is passing the first detection area A_(DET), the voltage difference between the positive input terminal V+ and the negative input terminal V− is influenced by an electrical charge of the particle P₁ to have a voltage variation, and the differential amplifier 1011 may amplify the voltage variation of the voltage difference to generate the first detection result R_(DET), which is an impulse signal, to the control module 103. In other words, when the particle P₁ is passing the first detection area A_(DET), a resistance of the first detection area A_(DET) is changed, such that the first detection circuit 11 is capable of detecting the existence of the particle P₁ to output the first detection result R_(DET).

Therefore, the first detection circuit 11 may output different impulse signals, i.e. the first detection result R_(DET) to the control module 103 according to different particle characteristics of the particle P₁, such as volume, electrical charge quantity and so on. The control module 103 may further comprise a storage unit 1031 for storing the first detection result R_(DET) and the turn-on time T_(ON) corresponding to different particle characteristics, such that the control module 103 may select the turn-on time T_(ON) of the light emission source 102 accordingly. As a result, the biological particle analyzer 10 may precisely control the turn-on time T_(ON) of the light emission source 102 according to different particle characteristics.

The first embodiment describes the light emission source 102 being turned on by the turn-on time T_(ON) as soon as the particle P₁ has arrived at the first detection area A_(DET). In the second embodiment of present invention, as shown in FIG. 1C, a difference between the first embodiment and the second embodiment is that there is a delay time T after the particle P₁ has arrived at the first detection area A_(DET) and the light emission source 102 is turned on after the delay time T is elapsed. Specifically, the control module 103 may set the delay time T counted by the timer 104, the light emission source 102 is turned on for the predetermined turn-on time T_(ON) when the delay time T elapsed and the particle P₁ is going to arrive at the excitation area A_(EXT). The storage unit 1031 may store the delay time T and the turn-on time T_(ON) according to different particle characteristics, and the timer 104 may time the delay time T and the turn-on time T_(ON), which allows the biological particle analyzer 10 to automatically turn on or off the light emission source 102.

Operations of the biological particle analyzer 10 in the first and second embodiments may be summarized into a biological particle analysis process P10, as shown in FIG. 1D. The biological particle analysis process P10 comprises the following steps:

Step S10: Start.

Step S11: The first detection circuit 11 outputs the first detection result R_(DET) when at least one particle P₁ has arrived at the first detection area A_(DET).

Step S12: The control module 103 sets the delay time T and the turn-on time T_(ON) according to the first detection result R_(DET).

Step S13: The timer 104 performs timing until the delay time T has elapsed, the control module 103 outputs the control signal CTRL to turn on the light emission source 102.

Step S14: Check whether the first detect result R_(DET) indicates to the control module 103 there is the second particle P₂ that has arrived at the first detection area A_(DET) during the turn-on time T_(ON) timed by the timer 104, if yes, go to Step S12; if no, go to Step S15.

Step S15: The control module 103 outputs the control signal CTRL to turn off the light emission source 102.

Step S16: End.

Please note that the steps S10-S15 of the biological particle analysis process P10 are used for the biological particle analyzer 10 shown in FIG. 1C. For the biological particle analyzer 10 shown in FIG. 1A, steps S12 and S13 for setting the delay time T may be omitted, which may be regarded as the delay time T is zero, i.e. T=0. Details of the biological particle analysis process P10 may be obtained by referring to descriptions of the biological particle analyzer 10, which is omitted herein.

Furthermore, an average velocity of the particle P₁ flowing in the microchannel may be calculated to obtain an arrival time of the particle P₁ arriving at the excitation area A_(EXT), so as to more precisely determine the turn-on time T_(ON) for turning on the light emission source 102. For example, please refer to FIG. 2A, which is a schematic diagram of a biological particle analyzer 20 according to a third embodiment of the present invention. The biological particle analyzer 20 comprises a microchannel 200, a first detection circuit 21, a second detection circuit 22, a control module 203, a timer 204 and drive electrodes V_(CC) and V_(SS). The first detection circuit 21 is coupled to a the first detection area A_(DET) close to the drive electrode V_(CC) of the microchannel 200, the first detection circuit 21 is used for outputting a the first detection result R_(DET) to the control module 203. The second detection circuit 22 is coupled to a second detection area A_(DET-2) between a downstream location of the first detection area A_(DET) and the excitation area A_(EXT) of the microchannel 20. The second detection circuit 22 is used for outputting a second detection result R_(DET-2) to the control module 203.

A shown in FIG. 2A, the second detection area A_(DET-2) is located between the first detection area A_(DET) and the excitation area A_(EXT). There is a distance d₁ between the second detection area A_(DET-2) and the first detection area A_(DET) and a distance d₂ between the second detection area A_(DET-2) and the excitation area A_(EXT). When the particle P₁ sequentially arrives at the first detection area A_(DET) and the second detection area A_(DET-2)/the first detection circuit 21 and the second detection circuit 22 respectively outputs the first detection result R_(DET) and the second detection result R_(DET-2) to the control module 203. The control module 203 may calculate an elapsed time T₁ of the particle P₁ flowing from the first detection area A_(DET) to the second detection area A_(DET-2) according to the first detection result R_(DET) and the second detection result R_(DET-2). The control module 203 may also calculate an average velocity V₁ of the particle P₁ according to the elapsed time T₁ and the distance d₁. Specifically, the timer 204 starts timing as soon as the control module 203 receives the first detection result R_(DET), and the timer 204 stops timing when the control module 203 receives the second detection result R_(DET-2), wherein the elapsed time T₁ is the time that the particle P₁ flowing from the first detection area A_(DET) to the second detection area A_(DET-2). As a result, the control module 203 may calculate the average velocity V₁ of the particle P₁ according to elapsed time T₁ and distance d₁, i.e. V₁=d₁/T₁. Then, the control module 203 may calculate an arrival time T₂ of the particle P₁ arriving at the excitation area A_(EXT) according to the average velocity V₁ and the distance d₂, i.e. T₂=V₁/d₂, so that the control module 203 may output the control signal CTRL to turn on the light emission source 202 at the arrival time T₂ and keep the light emission source 202 turned on during the turn-on time T_(ON).

Similar to the first embodiment, if the first detection circuit 21 detects another particle P₂ has arrived at the detection area A_(DET) before the light emission source 202 is turned off, i.e. during the turn-on time T_(ON), the control module 203 may recalculate the arrival time T₂ and extend the turn-on time T_(ON) of the light emission source 202 until the particle P₂ has left the excitation area A_(EXT) according to the latest received first detection result R_(DET) and the second detection result R_(DET-2). Noticeably, in practice, the biological particle analyzer 20 may test a plurality of particles at the same time, a designer may adjust the turn-on time T_(ON) to turn on light emission source 202 according to numbers of the plurality of particles. For example, there are at least two cases that may happen when two or more particles P₁ and P₂ are tested at the same test process.

Case (1): The particle P₁ is in the excitation area A_(EXT), which means the light emission source 202 is turned on during the turn-on time T_(ON), and the particle P₂ has left the first detection area A_(DET) but has not arrived at the second detection area A_(DET-2). When case (1) happens, although the turn-on time T_(ON) has elapsed, the control module 203 preferably keeps the light emission source 202 turned on until the particle P₂ has arrived at the second detection area A_(DET-2). Accordingly the control module 203 may calculate a new arrival time T₂ and a new turn-on time T_(ON) to reset the timer 204, and thus the light emission source 202 is kept turned on around (T₂+T_(ON)) until the particle P₂ is finished testing. If the arrival time T₂ of the particle P₂ arriving at the excitation area A_(EXT) is too short, e.g. a velocity of the particle P₂ is fast, such that the control module 203 may be too late to turn on the light emission source 202, which may cause the light emission source 202 to be turned on and off quickly in a short time, in order to protect the light emission source 202 and related circuits, the control module 203 preferably keeps the light emission source 202 turned on until the particle P₂ is finished testing. Therefore, in case (1), a real turn-on time of the light emission source 202 for testing the particles P₁ and P₂ may be different according to particle characteristics, flowing velocity or locations flowing to the first detection area A_(DET) and the second detection area A_(DET-2).

On the other hand, case (2): The particle P₁ remains in the excitation area A_(EXT), which means the light emission source 202 is turned on during the turn-on time T_(ON), and the particle P₂ has arrived at the second detection area A_(DET-2), the control module 203 recalculates a new arrival time T₂ and a new turn-on time T_(ON). When case (2) happens, the control module 203 may set a new arrival time T₂ and a new turn-on time T_(ON) and reset the timer 204 to keep the light emission source 202 turned on around (T₂+T_(ON)), until the particle P₂ is finished testing. In case (2), the real turn-on times of the light emission source 202 corresponding to the test procedures of the particles P₁ and P₂ may be different since the particles P₁ and P₂ may be distinct and have different properties and velocities or locations passing the excitation area A_(EXT).

As a result, the biological particle analyzer 20 may automatically turn on or off the light emission source 102 during the test procedure to save power consumption or prevent fast power switching. Furthermore, besides turning on the light emission source 202 during the turn-on time T_(ON) when the particles P₁ and P₂ are passing the excitation area A_(EXT), a designer may adjust a time that the light emission source 202 is turned on according to practical test conditions to have a flexible control time for turning on and off the light emission source 202.

Operations of the biological particle analyzer 20 in the third embodiment may be summarized into a biological particle analysis process P20, as shown in FIG. 2B. The biological particle analysis process P20 comprises the following steps:

Step S20: Start.

Step S21: When at least one first particle P₁ has arrived at the first detection area A_(DET), the first detection circuit 21 outputs the first detection result R_(DET) to the control module 203, and the control module 203 controls the timer 204 to start timing.

Step S22: When a least one first particle P₁ has arrived at the second detection area A_(DET-2), the second detection circuit 22 outputs the second detection result R_(DET-2) to the control module 203, and the control module 203 controls the timer 204 to stop timing.

Step S23: The control module 203 calculates the elapsed time T₁ of the first particle P₁ flowing from the first detection area A_(DET) to the second detection area A_(DET-2) according to the first detection result R_(DET) and the second detection result R_(DET-2), and calculates the average velocity V₁ of the first particle P₁ according to elapsed time T₁ and the first distance d₁.

Step S24: The control module 203 calculates the arrival time T₂ of the first particle P₁ arriving at the excitation area A_(EXT) according to the average velocity V₁ and the distance d₂.

Step S25: The control module 203 controls the timer 204 to start timing until the arrival time T₂ elapsed, the control module 203 outputs the control signal CTRL to turn on the light emission source 202.

Step S26: The control module 203 controls the timer 204 to start timing until the turn-on time T_(ON) when the control module 203 outputs the control signal CTRL to turn off the light emission source 202.

Step S27: End.

Details of the biological particle analysis process P20 may be obtained by referring to descriptions of the biological particle analyzer 20, which is omitted herein.

Furthermore, the second detection circuit 22 shown in FIG. 2A may be disposed close to the drive electrode V_(SS) in the microchannel 200 to have another method to determine when to turn on the light emission source 102. Please refer to FIG. 3A, which is a schematic diagram of a biological particle analyzer 30 according to a fourth embodiment of the present invention. As shown in FIG. 3A, a first detection circuit 31 of the biological particle analyzer 30 is coupled to the first detection area A_(DET) close to the drive electrode V_(CC) in the microchannel 300, the first detection circuit 31 is used for outputting the first detection result R_(DET) to control module 303. The second detection circuit 32 is coupled to a detection area A_(DET-3) at a downstream of the excitation area A_(EXT) in the microchannel 300, i.e. the excitation area A_(EXT) is located between the first detection area A_(DET) and the second detection area A_(DET-3).

In such a structure, when the particle P₁ has arrived at the first detection area A_(DET), the first detection circuit 31 may output the first detection result R_(DET) to the control module 303. The control module 303 may output the control signal CTRL to the light emission source 302 to turn on the light emission source 302. When the particle P₁ has arrived at the second detection area A_(DET-3), the second detection circuit 32 may output the second detection result R_(DET-3) to the control module 303, such that the control module 303 may output the control signal CTRL to the light emission source 302 to turn off the light emission source 302.

Noticeably, the control module 303 may further comprise a counter 305 for respectively counting particle numbers N_(IN) and N_(OUT) when at least one particle has arrived at the first detection area A_(DET) and the second detection area A_(DET-3), so as to determine to turn on or off the light emission source 302. Specifically, when the particle P₁ is about to flow in the microchannel 300, the counter 305 defaulted the particle numbers N_(IN) and N_(OUT) to be zero, the detection circuit 301 may detect the particle P₁ has arrived at the first detection area A_(DET) and output the first detection result R_(DET) to the control module 303. The control module 303 increases the particle number N_(IN) of the counter 305 by 1, and outputs the control signal CTRL to the light emission source 302 to turn on light emission source 302. When the particle P₁ sequentially arrives at the excitation area A_(EXT) and the second detection area A_(DET-3), which means the particle P₁ has been fully tested, the second detection circuit 32 may output the second detection result R_(DET-3) to the control module 303, and control module 303 may increase the particle number N_(OUT) of the counter 305 by 1. Therefore, when the particle number N_(IN) is equal to the particle number N_(OUT), i.e. N_(IN)=N_(OUT), the control module 303 may confirm the particle P₁ has beef fully tested, after which, the control module 303 may output the control signal CTRL to the light emission source 302 to turn off light emission source 302.

For example, when test two or more of the particles P₁ and P₂, the control module 303 may count the particle number N_(IN) to be 2 to turn on the light emission source 302 according to the first detection result R_(DET) outputted by the first detection circuit 31. Then, the control module 303 counts the particle number N_(OUT) to be 2 according to the second detection result R_(DET-3) outputted by the second detection circuit 32, and outputs the control signal CTRL to the light emission source 302 to turn off the light emission source 302. As a result, the control module 303 may respectively record that the particle numbers N_(IN) and N_(OUT) indicated the particles have arrived at the first detection area A_(DET) and the second detection area A_(DET-3), so as to determine to turn on or off the light emission source 302, which allows the biological particle analyzer 30 to automatically turn on or off the light emission source 302 during the test procedure to reduce power consumption.

Operations of the biological particle analyzer 30 may be summarized into a biological particle analysis process P30, as shown in FIG. 3B. The biological particle analysis process P30 comprises the following steps:

Step S30: Start.

Step S31: Calculate the particle number N_(IN) according to the first detection result R_(DET) outputted by the first detection circuit 31 when at least one first particle P₁ has arrived at the first detection area A_(DET), and outputting the control signal CTRL to turn on the light emission source 302 if the particle number N_(IN) is not zero.

Step S32: Calculate the particle number N_(OUT) according to the second detection result R_(DET-3) outputted by the second detection circuit 32 when the first particle P₁ has arrived at the second detection area A_(DET-2).

Step S33: Compare whether the particle number N_(IN) is equal to the particle number N_(OUT), if yes, go to Step S34; if no, go to Step S32.

Step S34: Output the control signal CTRL to turn off the light emission source 302.

Step S35: End.

Details of the biological particle analysis process P30 may be obtained by referring to descriptions of the biological particle analyzer 30, which is omitted herein.

Please note that the timer described in the above mentioned embodiments is built into the control module, which is not limiting, those skilled in the art may realized that the timer may be integrated in other circuits or devices of the biological particle analyzer, as long as the timer may be controlled by the control module to perform counting time and/or clocking.

To sum up, when the traditional biological particle analyzer is operating, the light emission source for emitting a light to the particles consumes most of power of the biological particle analyzer, and the light emission source is often turned on no matter whether a test procedure is being performed, which not only wastes power but also produces a significant amount of heat. The significant amount of heat may reduce battery life, influence usage convenience, deteriorate product reliability and increase production costs. In comparison, the biological particle analyzers 10, 20 and 30 of the present invention may have different detection methods or judgment parameters, such as setting the turn-on time of the light emission source, calculating the average velocity of the particle to evaluate the arrival time of the particle arriving at the light emission source, or calculating the number of the particles to determine to turn on or off the light emission source. Thus, the biological particle analyzers 10, 20 and 30 may automatically turn on or off the light emission source to save unnecessary power consumption, which achieves smart power savings. As a result, the biological particle analyzers 10, 20 and 30 of the present invention may effectively reduce power consumption, extend battery life and increase product reliability, or reduce a volume of a battery, which reduces a size and production cost of the biological particle analyzer and also facilitates a birth of a miniature biological particle analyzer.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. 

What is claimed is:
 1. A biological particle analyzer comprising: a microchannel including an end coupled to a first drive electrode, another end coupled to a second drive electrode, a first detection area at an upstream location and an excitation area at a downstream location for containing particles to flow from the upstream location to the down stream location inside the microchannel; a first detection circuit coupled to the first detection area for outputting a first detection result when at least one particle has arrived at the first detection area; a light emission source for emitting a light to the excitation area; a second detection circuit coupled to a second detection area located at a downstream location of the first detection area inside the microchannel for outputting a second detection result to the control module when the particles have arrived at the second detection area; and a control module coupled to the first detection circuit, the second detection circuit and the light emission source for determining when to turn on or off the light emission source according to the first detection result to save power consumption of the light emission source; wherein the control module is configured to calculate a turn-on time according to different particle characteristics and an average velocity of the at least one particle, and the light emission source is turned on only when the at least one particle is being tested during the turn-on time; wherein when the first detection result indicates that a first particle of the at least one particle has arrived at the first detection area, the control module outputs the control signal to the light emission source to turn on the light emission source, and when the second detection result indicates that the first particle has arrived at the second detection area, the control module outputs the control signal to the light emission source to turn off the light emission source; wherein the control module further comprises a counter for recording a first particle number when the first particle of the at least one particle has arrived at the first detection area and a second particle number when the first particle of the at least one particle has arrived at the second detection area to determine to turn on or off the light emission source.
 2. The biological particle analyzer of claim 1, wherein the control module further comprises a timer.
 3. The biological particle analyzer of claim 2, wherein when the first detection result indicates a first particle has arrived at the first detection area, the control module outputs a control signal to turn on the light emission source for the turn-on time timed by the timer.
 4. The biological particle analyzer of claim 3, wherein when the first detection result indicates a second particle has arrived at the first detection area during the turn-on time that the light emission source is turned on, a new turn-on time is reset by the timer so that the light emission source keeps lighting up the excitation area during the new turn-on time.
 5. The biological particle analyzer of claim 2, wherein when the first detection result indicates a first particle has arrived at the first detection area, the control module sets a delay time counted by the timer, and outputs a control signal to turn on the light emission source after the delay time elapsed, such that the light emission source lights up the excitation area for the turn-on time timed by the timer.
 6. The biological particle analyzer of claim 1, wherein the first detection circuit is a Resistive Pulse Sensor.
 7. The biological particle analyzer of claim 6, wherein the first drive electrode is applied to a positive drive voltage and the second drive electrode is applied to a negative drive voltage if the particle is positive electrically charged.
 8. The biological particle analyzer of claim 6, wherein the first drive electrode is applied to a negative drive voltage and the second drive electrode is applied to a positive drive voltage if the particle is negative electrically charged.
 9. The biological particle analyzer of claim 1, wherein the control module further comprises a storage unit for storing the detection result corresponding to the different particle characteristics to accordingly set the turn-on time and a turn-off time of the light emission source.
 10. The biological particle analyzer of claim 1, wherein the second detection area is located between the first detection area and the excitation area, there is a first distance between the first detection area and the second detection area, and a second distance between the second detection area and the excitation area.
 11. The biological particle analyzer of claim 10, wherein the control module calculates an elapsed time of the particle flowing from the first detection area to the second detection area according to the first detection result and the second detection result, and calculates the average velocity of the particle according to the elapsed time and the first distance.
 12. The biological particle analyzer of claim 11, wherein the control module comprises a timer, the timer starts timing as soon as the control module receives the first detection result, and the timer stops timing when the control module receives the second detection result, wherein the elapsed time is the time that the particle flowing from the first detection area to the second detection area.
 13. The biological particle analyzer of claim 11, wherein the control module calculates an arrival time according to the average velocity of the particle and the second distance, such that the control module outputs the control signal to the light emission source to turn on the light emission source for lighting up the excitation area during the turn-on time after the arrival time elapsed.
 14. The biological particle analyzer of claim 13, wherein when a first particle has arrived at the excitation area within the turn-on time, and the first detection result indicates a second particle has arrived at the first detection area, the control module extends the turn-on time of the light emission source until the second particle has arrived at the second detection area to generate the second detection result, the control module resets a new arrival time and a new turn-on time, such that the light emission source is turned on during the new arrival time and the new turn-on time until the second particle has arrived at the excitation area.
 15. The biological particle analyzer of claim 13, wherein when a first particle has arrived at the excitation area within the turn-on time, and the second detection result indicates a second particle has arrived at the second detection area, the control module resets a new arrival time and a new turn-on time, such that the light emission source is turned on during the new arrival time and the new turn-on time until the second particle arrived at the excitation area.
 16. The biological particle analyzer of claim 1, wherein the excitation area is located between the first detection area and the second detection area.
 17. The biological particle analyzer of claim 1, wherein if the first particle number is not zero, the control module outputs the control signal to the light emission source to turn on the light emission source.
 18. The biological particle analyzer of claim 1, wherein if the second particle number is equal to the first particle number, the control module outputs the control signal to the light emission source to turn off the light emission source.
 19. The biological particle analyzer of claim 1, wherein the biological particle analyzer is a Flow Cytometer. 